Generate a Factorio server-settings.json

Factorio's server-settings.json is strict JSON, and there is one particular rule in strict JSON that trips nearly everybody: no trailing commas.

Start from a preset

Visual Settings

json Format

Identity

name

Name shown in the public server browser.

description

Description in the browser.

server-settings.json

username — Public visibility needs valid Factorio account credentials. Without them the server runs but never appears in the browser or in a status check.

max_players — 0 means unlimited, not closed. Use a password or the visibility settings to restrict who can join.

{
  "name": "My Factory",
  "description": "The factory grows.",
  "tags": "",
  "max_players": 0,
  "game_password": "",
  "require_user_verification": true,
  "visibility_public": true,
  "visibility_lan": true,
  "username": "",
  "token": "",
  "autosave_interval": 10,
  "autosave_slots": 5,
  "afk_autokick_interval": 0,
  "allow_commands": "admins-only",
  "auto_pause": true,
  "non_blocking_saving": false
}

The server-settings.json format

Plain JSON, no extensions. No comments of any sort, no comma after the final item in an object, double quotes around strings, and no quotes around numbers or booleans. A quoted number is a genuine error here, not a harmless quirk — max_players given as "10" is text, and it will be refused where a number belongs.

The mistake that wastes an evening

Setting max_players to 0 does not close the server; it removes the limit. People enter 0 hoping to stop anyone joining and end up with a public server that has no cap at all. To close the server, use the visibility settings or a password, not the player limit.

Start from the example file

Factorio ships a complete, commented template at data/server-settings.example.json in the game folder. Copy it, edit the copy, and point the server at it with --server-settings when you start it; editing the example itself means an update can replace your settings. A new map is created separately, with --create and a save file name, and started with --start-server.

Admins are a separate file

Who counts as an admin is not in server-settings.json. It lives in server-adminlist.json, a plain list of Factorio usernames kept in the same folder as factorio-current.log. Promoting a player from the server console creates and updates it for you.

Mods on a server

Server mods sit in the mods folder, switched on and off in its mod-list.json. Players must run the same mods and versions to join, and the game offers to download and enable the server's set when they connect, so there is no need to send anyone a mod list by hand.

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